An eminent historian looks to the present and future of Afghanistan as the U.S. withdraws from the longest war in its history. THE BROOKINGS ESSAY: In the spirit of its commitment to high-quality, independent research, the Brookings Institution has commissioned works on major topics of public policy by distinguished authors, including Brookings scholars. The Brookings Essay is a multi-platform product aimed to engage readers in open dialogue and debate. The views expressed, however, are solely those of the author. Available in ebook only.